Abstract

Individual linear growth was studied in 23 specimens of the freshwater pearl mussel Margaritifera margaritifera by measuring successive annual growth rings on the shell surface. It is demonstrated that the growth of each mussel can be described by a single equation, of which a particular case is the von Bertalanffy equation with an average growth deceleration coefficient of a = 0.048 year^–1 and a coefficient of the initial conditions of d = 5.3 mm/year. It was observed that growth was accompanied by three regular biorhythms with periods of 12.6, 6.4, and 4.0 years, the first two being decaying biorhythms, while the latter had a constant amplitude. We ascertained that the decrease in the amplitude of the decaying biorhythms can be modeled by power equations. The nature of the biorhythms detected is discussed.

中文翻译：

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淡水珍珠贻贝 Margaritifera margaritifera (Bivalvia, Margaritiferidae), Nemina River 种群 (Karelia) 的生长生物节律

摘要

通过测量贝壳表面连续的年轮，研究了 23 个淡水珍珠贻贝Margaritifera margaritifera的个体线性生长。结果表明，每只贻贝的生长都可以用一个方程来描述，其中一个特例是 von Bertalanffy 方程，其平均生长减速系数为a = 0.048 year ^–1，初始条件系数为d= 5.3 毫米/年。观察到，生长伴随着三个规律的生物节律，周期为 12.6、6.4 和 4.0 年，前两个是衰减的生物节律，而后者具有恒定的幅度。我们确定衰减生物节律幅度的减小可以通过功率方程建模。讨论了检测到的生物节律的性质。